Thermoplastic resin composition and moldings thereof

ABSTRACT

A polyamide resin/rubber-reinforced styrene-based resin composition, particularly, a polyamide resin/ABS resin composition, excellent in the balance between impact strength and fluidity as well as in the heat resistance, chemical resistance and paintability, as well as a shaped article thereof, are provided. The resin composition comprises 100 parts by weight of a thermoplastic resin comprising (A) from 79.5 to 20 parts by weight of a polyamide resin, (B) from 20 to 79.5 parts by weight of a polymer obtained by grafting an aromatic vinyl-based monomer and a vinyl cyanide-based monomer to a specific rubber-like polymer, (C) from 0.5 to 60 parts by weight of an unsaturated carboxylic acid-modified copolymer obtained by copolymerizing an unsaturated carboxylic acid, an aromatic vinyl-based monomer and a vinyl cyanide-based monomer, and (D) from 0 to 50 parts by weight of a copolymer obtained by copolymerizing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer (with the proviso that the total of (A), (B), (C) and (D) is 100 parts by weight), and if desired, further comprises (E) from 0.05 to 150 parts by weight of an inorganic filler.

TECHNICAL FIELD

The present invention relates to a thermoplastic resin compositionexcellent in the balance between impact strength, particularly, impactstrength at low temperatures, and fluidity as well as in the heatresistance, chemical resistance and paintability, and also relates to ashaped article thereof.

BACKGROUND ART

Polyamide resin is excellent in the chemical resistance, mechanicalstrength, heat resistance, abrasion resistance and the like and iswidely used for electric-electronic parts, machine parts and automobileparts. However, this resin is disadvantageously poor in the impactstrength. On the other hand, a rubber-reinforced styrene-based resinsuch as HIPS (high-impact styrene copolymer resin), ABS resin(acrylonitrile-butadiene-styrene copolymer resin), AES resin(acrylonitrile-ethylene-propylene-based rubber-styrene copolymer resin)and AAS resin (acrylonitrile-acryl-based rubber-styrene copolymer resin)is excellent in impact strength and shapability and is also widely usedfor automobile parts, office appliance parts, electric parts and thelike, but this resin is disadvantageously inferior in chemicalresistance and abrasion resistance.

In order to mutually redeem these disadvantages of respective resins, ablend of polyamide resin and ABS resin has been proposed (see, forexample, Japanese Examined Patent Publication (Kokoku) No. 38-23476).However, compatibility between polyamide resin and ABS resin is low andtherefore, a technique of copolymerizing an unsaturated carboxylic acidwith styrene or acrylonitrile and blending the obtained unsaturatedcarboxylic acid-modified copolymer as a compatibilizer to the polyamideresin and ABS resin has been proposed (see, for example, JapaneseExamined Patent Publication (Kokoku) No. 7-84549). With such animprovement in the compatibility, the impact strength is also enhancedto a certain extent.

However, with recent progress in increasing the size and reducing thethickness of home appliance parts, automobile parts and the like, apolyamide resin/rubber-reinforced styrene-based resin composition,particularly, a polyamide resin/ABS resin composition, excellent in thefluidity as well as in the impact strength is demanded to enhance theshaping cycle and increase the productivity.

To meet this requirement, a technique of using an unsaturated carboxylicacid-modified copolymer having a reduced viscosity within a limitedrange as a compatibilizer and thereby balancing the impact strength andthe fluidity has been proposed, but its effect is not yet satisfactory(see, Japanese Unexamined Patent Publication (Kokai) No. 2000-17170).

The present invention has been made to solve those problems in thepolyamide resin/rubber-reinforced styrene-based resin composition, andan object of the present invention is to provide a polyamideresin/rubber-reinforced styrene-based resin composition, particularly, apolyamide resin/ABS resin composition, excellent in balance betweenimpact strength and fluidity as well as in heat resistance, chemicalresistance and paintability.

DISCLOSURE OF THE INVENTION

According to the present invention, in order to attain theabove-described object, the following are provided.

[1] A thermoplastic resin composition comprising the followingcomponents:

-   -   (A) from 20 to 79.5 parts by weight of a polyamide resin;    -   (B) from 20 to 79.5 parts by weight of a graft polymer, the        graft polymer being obtained by,        -   (a) in the presence of from 40 to 80 wt % of a rubber-like            polymer having a swell index of 10 to 80 and a weight            average particle diameter of 100 to 600 nm,        -   (b) graft-polymerizing from 20 to 60 wt % of a monomer            mixture comprising:        -   (i) from 50 to 90 wt % of an aromatic vinyl-based monomer,        -   (ii) from 10 to 50 wt % of a vinyl cyanide-based monomer,            and        -   (iii) from 0 to 30 wt % of another vinyl monomer            copolymerizable with those monomers,        -   in which the acetone-soluble moiety of the graft polymer (B)            has a number average molecular weight of 20,000 to 200,000;    -   (C) from 0.5 to 60 parts by weight of an unsaturated carboxylic        acid-modified polymer,        -   the unsaturated carboxylic acid-modified polymer being            obtained by copolymerizing from 0.05 to 20 wt % of an            unsaturated carboxylic acid monomer, from 50 to 89.95 wt %            of an aromatic vinyl-based monomer and from 10 to 49.95 wt %            of a vinyl cyanide-based monomer, and having a number            average molecular weight of 22,000 to 60,000; and    -   (D) from 0 to 50 parts by weight of a copolymer,        -   the copolymer being obtained by copolymerizing from 50 to 90            wt % of an aromatic vinyl monomer, from 10 to 50 wt % of a            vinyl cyanide-based monomer and from 0 to 60 wt % of another            vinyl-based monomer copolymerizable with those monomers;            with the proviso that the total amount of the components (A)            to (D) is 100 parts by weight.

[2] A thermoplastic resin composition comprising the followingcomponents:

-   -   (A) from 20 to 79.5 parts by weight of a polyamide resin;    -   (B) from 20 to 79.5 parts by weight of a graft polymer,        -   the graft polymer being obtained by,        -   (a) in the presence of from 40 to 80 wt % of a rubber-like            polymer having a swell index of 10 to 80 and a weight            average particle diameter of 100 to 600 nm,        -   (b) graft-polymerizing from 20 to 60 wt % of a monomer            mixture comprising:        -   (i) from 50 to 90 wt % of an aromatic vinyl-based monomer,        -   (ii) from 10 to 50 wt % of a vinyl cyanide-based monomer,            and        -   (iii) from 0 to 30 wt % of another vinyl monomer            copolymerizable with those monomers,        -   in which the acetone-soluble moiety has a number average            molecular weight of 20,000 to 200,000;    -   (C) from 0.5 to 60 parts by weight of an unsaturated carboxylic        acid-modified polymer,        -   the unsaturated carboxylic acid-modified polymer being            obtained by copolymerizing from 0.05 to 20 wt % of an            unsaturated carboxylic acid monomer, from 50 to 89.95 wt %            of an aromatic vinyl-based monomer and from 10 to 49.95 wt %            of a vinyl cyanide-based monomer, and having a number            average molecular weight of 22,000 to 60,000;    -   (D) from 0 to 50 parts by weight of a copolymer,        -   the copolymer being obtained by copolymerizing from 50 to 90            wt % of an aromatic vinyl monomer, from 10 to 50 wt % of a            vinyl cyanide-based monomer and from 0 to 60 wt % of another            vinyl-based monomer copolymerizable with those monomers;            with the proviso that the total amount of the components (A)            to (D) is 100 parts by weight; and    -   (E) from 0.05 to 150 parts by weight of an inorganic filler.

[3] The thermoplastic resin composition as described in [2], wherein thenumber average molecular weight of the polyamide resin is from 10,000 to20,000.

[4] The thermoplastic resin composition as described in any one of [α]to[3], wherein the graft polymer is obtained by graft-polymerizing styreneand acrylonitrile in the presence of a rubber-like polymer.

[5] The thermoplastic resin composition as described in [1] to [4],wherein the amount of the unsaturated carboxylic acid monomer in theunsaturated carboxylic acid-modified copolymer is from 0.5 to 10 wt %.

[6] The thermoplastic resin composition as described in [1] to [4],wherein the amount of the unsaturated carboxylic acid monomer in theunsaturated carboxylic acid-modified copolymer is from 0.8 to 7 wt %.

[7] The thermoplastic resin composition as described in [1] to [6],wherein the unsaturated carboxylic acid in the unsaturated carboxylicacid-modified copolymer is methacrylic acid.

[8] The thermoplastic resin composition as described in [1] to [7],wherein the unsaturated carboxylic acid-modified copolymer is obtainedby copolymerizing methacrylic acid, styrene and acrylonitrile.

[9] The thermoplastic resin composition as described in [1] to [8],which comprises the rubber-like polymer in the range from 8 to 40 wt %.

[10] The thermoplastic resin composition as described in [1] to [8],which comprises the rubber-like polymer in the range from 10 to 25 wt %.

[11] The thermoplastic resin composition as described in [2] to [10],wherein the inorganic filler is a layered silicate with one unit havinga one-side length of 0.002 to 1 pn and a thickness of 6 to 20 Å.

[12] A shaped article comprising the thermoplastic resin compositiondescribed in [1] to [11].

[13] An automobile part obtained by shaping the thermoplastic resincomposition described in [1] to [11].

MODE FOR CARRYING OUT THE INVENTION

Examples of the polyamide resin (A) for use in the present inventioninclude nylon 6, nylon 46, nylon 66, nylon 69, nylon 610, nylon 612,nylon 116, nylon 4, nylon 7, nylon 8, nylon 11, nylon 12, nylon 6I,nylon 6/66, nylon 6T/6I, nylon 6/6T, nylon 66/6T,polytrimethylhexamethylene terephthalamide,polybis(4-aminocyclohexyl)methane dodecamide,polybis(3-methyl-4-aminocyclohexyl)methane dodecamide, polymetaxylyleneadipamide, nylon 11T, polyundecamethylene hexahydroterephthalamide andpolyamide elastomer. In these examples, I represents an isophthalic acidcomponent and T represents a terephthalic acid component. Among these,nylon 6, nylon 46, nylon 66, nylon 12, nylon 6T/6I, nylon 6/6T and nylon66/6T are preferred.

In the case where an inorganic filler is contained, the polyamide resin(A) for use in the present invention has a number average molecularweight of 10,000 to 20,000. If the number average molecular weight isless than 10,000, the impact strength disadvantageously decreases,whereas if the number average molecular weight exceeds 20,000, thefluidity disadvantageously decreases.

In the thermoplastic resin composition of the present invention, thepolyamide resin (A) is used in an amount of 20 to 79.5 parts by weight,preferably from 20 to 70 parts by weight, with the proviso that thetotal amount of the components (A) to (D) is 100 parts by weight. If theamount of the polyamide resin is less than 20 parts by weight, poorchemical resistance results, whereas if it exceeds 79.5 parts by weight,the impact strength decreases.

In the present invention, the graft polymer (B) is a polymer obtained bygraft-polymerizing from 60 to 20 wt % of a monomer mixture comprisingfrom 90 to 50 wt % of an aromatic vinyl-based monomer, from 10 to 50 wtof a vinyl cyanide-based monomer and from 0 to 30 wt % of another vinylmonomer copolymerizable with those monomers in the presence of from 40to 80 wt % of a rubber-like polymer having a swell index of 10 to 80 anda weight average particle diameter of 100 to 600 nm, in which theacetone-soluble moiety of the graft polymer (B) has a number averagemolecular weight of 20,000 to 200,000.

Examples of the rubber-like polymer for use in the graft copolymer (B)include conjugated diene rubbers, conjugated diene-based polymers suchas a copolymer of a conjugated diene and a vinyl-based monomercopolymerizable therewith, acryl ester-based polymers such as an acrylicacid ester polymer and a copolymer of an acrylic acid ester and avinyl-based monomer copolymerizable therewith,ethylene-propylene-non-conjugated diene copolymers orbutene-propylene-non-conjugated diene copolymers, andpolyorganosiloxane-based polymers.

Examples of the vinyl-based monomer copolymerizable with a conjugateddiene-based monomer or an acrylic acid ester include aromaticvinyl-based monomers such as styrene and α-methylstyrene, vinylcyanide-based monomers such as acrylonitrile and methacrylonitrile, andunsaturated carboxylic acid alkyl ester-based monomers such as methylacrylate, ethyl acrylate and methyl methacrylate.

Accordingly, specific examples of the rubber-like polymer includepolybutadiene, polyisoprene, a butadiene-styrene copolymer, abutadiene-acrylonitrile copolymer and a butadiene-methyl methacrylatecopolymer, with polybutadiene and a butadiene-styrene copolymer beingpreferred.

Examples of the acrylic acid ester in the acrylic acid ester polymerinclude methyl acrylate, ethyl acrylate, propyl acrylate, butylacrylate, isobutyl acrylate, pentyl acrylate, isoamyl acrylate, n-hexylacrylate, 2-methylpentyl acrylate, 2-ethylhexyl acrylate and n-octylacrylate. Among these, butyl acrylate and isobutyl acrylate arepreferred.

Examples of the diene contained in the ethylene-propylene-non-conjugateddiene copolymer include dicyclopentadiene, 1,4-hexadiene,1,4-heptadiene, 1,5-cyclooctadiene, 6-methyl-1,5-heptadiene,11-ethyl-1,11-tridecadiene and 5-methylene-2-norbornene.

Out of these rubber-like polymers, one polymer may be used alone, or twoor more polymers may be used as a composite rubber.

According to the present invention, the graft polymer (B) can beobtained by graft-polymerizing an aromatic vinyl-based monomer, a vinylcyanide-based monomer and if desired, another vinyl monomercopolymerizable with these monomers to the above-described rubber-likepolymer. Examples of the aromatic vinyl-based monomer include styrene,α-methylstyrene, p-methylstyrene, chlorostyrene and bromostyrene. Thesemonomers are used individually or as a mixture of two or more thereof.Among these, styrene and α-methylstyrene are preferred. Examples of thevinyl cyanide-based monomer include acrylonitrile and methacrylonitrile.These monomers are also used individually or as a mixture of two or morethereof. In particular, acrylonitrile is preferred.

Examples of the another vinyl monomer copolymerizable with thesearomatic vinyl-based monomer and vinyl cyanide-based monomer includemaleimide-based monomers such as maleimide, methylmaleimide,ethylmaleimide, N-phenylmaleimide and O-chloro-N-phenylmaleimide, andunsaturated carboxylic acid ester-based monomers such as methylacrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and2-ethylhexyl acrylate.

According to the present invention, the rubber-like polymer in thethus-obtained graft polymer (B) has a swell index of 10 to 80,preferably from 15 to 50, more preferably from 25 to 45. The swell indexis a value measured and calculated as follows. That is, a latex iscoagulated and dried, about 1 g of the polymer is then preciselyweighed, immersed in about 50 g of toluene and left standing at 23° C.for 48 hours to swell the polymer, and thereafter extra toluene isremoved by decantation. The swelled polymer is precisely weighed withoutdelay and then dried under reduced pressure at 80° C. for 24 hours.After the absorbed toluene is removed by evaporation, the polymer isagain precisely weighed, and the swell index is calculated according tothe following formula.Swell index={(weight of swelled polymer)−(weight of driedpolymer)}/(weight of dried polymer)

In the present invention, if the swell index of the rubber-like polymerfor use in the production of the graft polymer (B) is less than 10 orexceeds 80, the impact strength of the thermoplastic resin compositionobtained is extremely low.

According to the present invention, the weight average particle diameterof the rubber-like polymer in the graft polymer (B) is preferably from100 to 600 nm, more preferably from 150 to 450 nm. In the presentinvention, it is preferred that a diene-based rubber latex particlecomprising the rubber polymer having the above-described swell index andweight average particle diameter is obtained by various methods asdescribed later and in the presence of this diene-based rubber latexparticle as-is or after enlargement by aggregation, those aromaticvinyl-based monomer and vinyl cyanide-based monomer aregraft-polymerized to obtain the graft polymer. For enlarging thediene-based rubber latex particle by aggregation, as is well known, theparticles may be mechanically aggregated or an acidic substance may beadded to the latex.

According to the present invention, the acetone-soluble moiety in thegraft polymer (B) has a number average molecular weight of 20,000 to200,000. If the number average molecular weight of the acetone-solublemoiety in the graft polymer is less than 20,000, the thermoplastic resincomposition obtained suffers from poor impact strength, whereas if itexceeds 200,000, the thermoplastic resin composition obtained exhibitspoor fluidity. In the present invention, the number average molecularweight of the acetone-soluble moiety in the graft polymer is preferablyfrom 20,000 to 100,000, more preferably from 20,000 to 60,000.

In the present invention, the method for producing such a graft polymeris not particularly limited and a conventionally known method may beused. For example, an emulsion polymerization method, a suspensionpolymerization method, a bulk polymerization method, a solutionpolymerization method or a combination thereof may be appropriatelyused.

In the thermoplastic resin composition of the present invention, thegraft polymer (B) is used in an amount of 20 to 79.5 parts by weight,preferably from 20 to 70 parts by weight, with the proviso that thetotal amount of the components (A) to (D) is 100 parts by weight. If theamount used is less than 20 parts by weight, the impact strengthdecreases, whereas if it exceeds 79.5 parts by weight, the fluiditydecreases.

According to the present invention, the unsaturated carboxylicacid-modified copolymer (C) is a copolymer obtained by copolymerizingfrom 0.05 to 20 wt %, preferably from 0.5 to 10 wt %, more preferablyfrom 0.8 to 7 wt % of an unsaturated carboxylic acid monomer, from 89.95to 50 wt %, preferably 89.5 to 55 wt %, more preferably from 84.2 to 60wt % of an aromatic vinyl-based monomer, and from 10 to 49.95 wt %,preferably from 10 to 44.5 wt %, more preferably from 15 to 39.2 wt % ofa vinyl cyanide-based monomer, and has a number average molecular weightof 22,000 to 60,000, preferably from 25,000 to 60,000.

Examples of the unsaturated carboxylic acid monomer constituting theunsaturated carboxylic acid-modified copolymer (C) include an acrylicacid, a methacrylic acid, a maleic acid, a fumaric acid and an itaconicacid. These monomers are used individually or as a mixture of two ormore thereof. Among these, a methacrylic acid is preferred. As for thearomatic vinyl-based monomer and vinyl cyanide-based monomer, the samecompounds as those used for the production of the graft polymer (B) canbe used.

In the present invention, a part of the aromatic vinyl-based monomerconstituting the unsaturated carboxylic acid-modified copolymer (C) canbe replaced by another vinyl-based monomer copolymerizable with thearomatic vinyl-based monomer, for example, by an unsaturated carboxylicacid ester-based monomer such as methyl acrylate, ethyl acrylate, butylacrylate, methyl methacrylate, ethyl methacrylate and 2-ethylhexylacrylate.

According to the present invention, the unsaturated carboxylicacid-modified copolymer must have a number average molecular weight of22,000 to 60,000 so as to obtain a resin composition excellent in thebalance between impact strength and fluidity. If the number averagemolecular weight of the unsaturated carboxylic acid-modified copolymer(C) is less than 22,000, the resin composition obtained is inferior inchemical resistance or paintability, whereas if it exceeds 60,000, theresin composition obtained exhibits poor fluidity. Here, the numberaverage molecular weight of the unsaturated carboxylic acid-modifiedcopolymer (C) is a molecular weight determined by dissolving thecopolymer in tetrahydrofuran and measuring its molecular weightaccording to the GPC method (gel permeation chromatography method).

In the unsaturated carboxylic acid-modified copolymer (C), if the amountof the unsaturated carboxylic acid monomer is less than 0.05 wt %, thiscopolymer exhibits poor compatibility in the resin composition and theobtained resin composition is inferior in the impact strength andpaintability, whereas if it exceeds 20 wt %, the fluidity of theobtained resin composition seriously decreases.

The unsaturated carboxylic acid-modified copolymer (C) is contained inan amount of 0.5 to 60 parts by weight, preferably from 1 to 35 parts byweight, with the proviso that the total of the components (A) to (D) inthe thermoplastic resin composition of the present invention is 100parts by weight. If the amount of the unsaturated carboxylicacid-modified copolymer (C) is less than 0.5 parts by weight, thiscopolymer is not uniformly dispersed in the resin composition and theobtained resin composition is inferior in the impact strength andpaintability, whereas if it exceeds 60 parts by weight, the obtainedresin composition exhibits poor fluidity.

According to the present invention, the unsaturated carboxylicacid-modified copolymer (C) having a number average molecular weight of22,000 to 60,000 and containing from 0.05 to 20 wt % of an unsaturatedcarboxylic acid monomer is blended in the resin composition within anappropriate range, whereby excellent compatibility can be obtainedbetween the polyamide resin and the styrene-based resin, and athermoplastic resin composition excellent in the balance between impactstrength and fluidity, particularly excellent in the impact strength atlow temperatures, can be obtained.

The unsaturated carboxylic acid-modified copolymer (C) is also notparticularly limited in its production method and can be obtained byappropriately using a conventionally known method such as emulsionpolymerization method, bulk polymerization method, suspensionpolymerization method and solution polymerization method. As is wellknown, the number average molecular weight of such an unsaturatedcarboxylic acid-modified copolymer (C) can be freely adjusted by thepolymerization temperature, the method of adding monomers used, the kindor the amount of the initiator, or that of the polymerization chaintransfer agent such as tert-dodecylmercaptane.

In the present invention, the copolymer (D) is a copolymer obtained bycopolymerizing from 90 to 50 wt % of an aromatic vinyl-based monomer,from 10 to 50 wt % of a vinyl cyanide-based monomer and from 0 to 60 wt% of another vinyl monomer copolymerizable with those monomers. Thecopolymer (D) is preferably a copolymer obtained by copolymerizing from90 to 55 wt % of an aromatic vinyl-based monomer, from 10 to 45 wt % ofa vinyl cyanide-based monomer and from 0 to 10 wt % of another vinylmonomer copolymerizable with those monomers.

As for the aromatic vinyl-based monomer and vinyl cyanide-based monomer,the same compounds as those used for the production of the graft polymer(B) can be used. Examples of the another vinyl monomer copolymerizablewith those monomers include maleimide-based monomers such as maleimide,methylmaleimide, ethylmaleimide, N-phenylmaleimide,N-cyclohexylmaleimide and O-chloro-N-phenylmaleimide, and unsaturatedcarboxylic acid ester-based monomers such as methyl acrylate, ethylacrylate, methyl methacrylate, ethyl methacrylate and 2-ethylhexylacrylate.

In the present invention, the weight average molecular weight of thecopolymer (D) is not particularly limited but is usually from 50,000 to250,000, preferably from 55,000 to 200,000. This copolymer (D) can beobtained by a conventionally known appropriate method such as anemulsion polymerization method, a bulk polymerization method, asuspension polymerization method and a solution polymerization method.

In the thermoplastic resin composition of the present invention, thecopolymer (D) is used in an amount of 0 to 50 parts by weight,preferably from 1 to 35 parts by weight, with the proviso that the totalamount of the components (A) to (D) is 100 parts by weight. If theamount used exceeds 50 parts by weight, the impact strength decreases.

As described above, the thermoplastic resin composition of the presentinvention comprises from 20 to 79.5 parts by weight of the polyamideresin (A), from 20 to 79.5 parts by weight of the graft polymer (B),from 0.5 to 60 parts by weight of the unsaturated carboxylicacid-modified copolymer (C) and from 0 to 50 parts by weight of thecopolymer (D) (with the proviso that the total of the components (A) to(D) is 100 parts by weight). If any one component departs from thisrange, a thermoplastic resin composition having desired propertiescannot be obtained.

Described in another way, the composition range is 100 parts by weightof the polyamide resin (A), from 30 to 300 parts by weight of the graftpolymer (B), from 1 to 250 parts by weight of the unsaturated carboxylicacid-modified copolymer (C) and from 0 to 120 parts by weight of thecopolymer (D), preferably 100 parts by weight of the polyamide resin(A), from 30 to 150 parts by weight of the graft polymer (B), from 1 to120 parts by weight of the unsaturated carboxylic acid-modifiedcopolymer (C) and from 0 to 120 parts by weight of the copolymer (D),more preferably 100 parts by weight of the polyamide resin (A), from 35to 130 parts by weight of the graft polymer (B), from 2 to 110 parts byweight of the unsaturated carboxylic acid-modified copolymer (C) andfrom 0 to 100 parts by weight of the copolymer (D).

Furthermore, in the present invention, the content of the rubber-likepolymer occupying in the entire resin composition is preferably from 8to 40 wt %, more preferably from 10 to 25 wt %, in view of balance inphysical properties of the thermoplastic resin composition obtained.

The inorganic filler (E) used in one preferred embodiment of the presentinvention includes a fibrous or non-fibrous inorganic filler. Specificexamples thereof include fibrous fillers such as glass fiber, carbonfiber, potassium titanate whisker, zinc oxide whisker, aluminum boratewhisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramicfiber, asbestos fiber, gypsum fiber and metal fiber, and non-fibrousfillers such as silicates (e.g., wollastonite, zeolite, sericite,kaolin, mica, clay, pyrophyllite, bentonite, montmorillonite, asbestos,talc, aluminosilicate), metal oxides (e.g., alumina, silicon oxide,magnesium oxide, zirconium oxide, titanium oxide, iron oxide),carbonates (e.g., calcium carbonate, magnesium carbonate, dolomite),sulfates (e.g., calcium sulfate, barium sulfate), hydroxides (e.g.,magnesium hydroxide, calcium hydroxide, aluminum hydroxide), glassbeads, ceramic beads, boron nitride, silicon carbide and silica. Theseinorganic fillers may have a hollow shape and may be used in combinationof two or more thereof. From the standpoint of obtaining more excellentmechanical strength, such a filler is preferably used afterpreliminarily treating it with a coupling agent such as anisocyanate-based compound, an acryl-based compound, an organicsilane-based compound, an organic titanate-based compound, an organicborane-based compound and an epoxy compound.

Among these inorganic fillers, the filler preferably used for enhancingthe heat resistance is a fibrous filler such as carbon fiber and glassfiber.

The fibrous filler has a fiber diameter of 0.01 to 20 μm, preferablyfrom 0.03 to 15 μm, and a fiber cut length of 0.5 to 10 mm, preferablyfrom 0.7 to 6 mm.

The amount used of the inorganic filler (E), for use in the presentinvention, is from 0.05 to 150 parts by weight per 100 parts by weightof the thermoplastic resin comprising the components (A), (B), (C) and(D). If the amount used is less than 0.05 parts by weight, the effect ofenhancing the mechanical strength and heat resistance is small, whereasif it exceeds 150 parts by weight, the shapability or surface statedisadvantageously changes for the worse. In the case of using a fibrousfiller as the inorganic filler (E), the amount used is preferably from 5to 100 parts by weight.

A layered silicate may also be used as the inorganic filler (E) for usein the present invention. When a layered silicate is used, an effect ofenhancing the mechanical strength and heat resistance can be obtained bythe addition in a small amount and therefore, the fluidity or surfaceproperty is improved.

The amount used of the layered silicate is preferably from 0.05 to 30parts by weight, more preferably from 0.1 to 10 parts by weight, per 100parts by weight of the thermoplastic resin. If the proportion of thelayered silicate is less than 0.05 parts by weight, the effect ofenhancing the mechanical strength and heat resistance is small, whereasif it exceeds 30 parts by weight, the fluidity decreases extremely andpoor shapability disadvantageously results.

Examples of the layered silicate include layered phyllosilicatesconstructed of layers of magnesium silicate or aluminum silicate.

Specific examples of the layered phyllosilicate include smectite clayminerals such as montmorillonite, saponite, beidellite, nontronite,hectorite and stevensite, as well as vermiculite and halloysite. Thesemay be a natural product or a synthetic product. Among these layeredsilicates, montmorillonite is preferred.

The layered silicate may be dispersed in the entire thermoplastic resincomprising the components (A), (B), (C) and (D) or may be dispersed inat least one resin, but is preferably in a state of being uniformlydispersed in the resin.

The state that the layered silicate is uniformly dispersed is such astate that when a layered silicate having a one-side length of 0.002 to1 μm and a thickness of 6 to 20 Å is dispersed in a resin, the layeredsilicate is uniformly dispersed while maintaining an interlayer distanceof 20 Å or more on average. The interlayer distance as used herein meansa distance between the gravitational centers of plates of the layeredsilicate, and the uniformly dispersed state means that multilayermaterials each having a structure where the plates of the layeredsilicate are stacked in five layers or less on average are dispersed inparallel, at random or in a mixed form thereof and 50 wt % or more,preferably 70 wt % or more, of the multilayer materials are dispersedwithout locally forming a mass.

In the case where the layered silicate is a multilayer clay mineral, thelayered silicate may also be uniformly dispersed by performing thepolymerization after contacting the layered silicate with a swellingagent such as amine (e.g., dioctadecylamine, phenylenediamine), aminoacid (e.g., 4-amino-n-butyric acid, 12-aminododecanoic acid) or lactams(e.g., ε-caprolactam) to previously expand the space between layers andthereby facilitate the intercalation of monomers between layers. Also, amethod of previously expanding the space between layers to 20 Å or moreby using a swelling agent and then melt-mixing the layered silicate withthe resin, thereby uniformly dispersing the layered silicate, may beused.

As described above, the thermoplastic resin composition of the presentinvention comprises 100 parts by weight of the thermoplastic resincomprising from 79.5 to 20 parts by weight, preferably from 70 to 20parts by weight of the polyamide resin (A), from 20 to 79.5 parts byweight, preferably from 20 to 70 parts by weight of the graft polymer(B), from 0.5 to 60 parts by weight, preferably from 1 to 35 parts byweight of the unsaturated carboxylic acid-modified copolymer (C) andfrom 0 to 50 parts by weight, preferably from 1 to 35 parts by weight ofthe copolymer (D) (with the proviso that the total of (A), (B), (C) and(D) is 100 parts by weight), and from 0.05 to 150 parts by weight of theinorganic filler (E). If any one component departs from this range, athermoplastic resin composition having desired properties cannot beobtained. Particularly, in the present invention, the content of therubber-like polymer occupying in the entire resin composition ispreferably from 8 to 40 wt % in view of balance in physical propertiesof the thermoplastic resin composition obtained.

The thermoplastic resin composition of the present invention can beobtained by uniformly melt-mixing the above-described polyamide resin(A), graft polymer (B), unsaturated carboxylic acid-modified copolymer(C) and copolymer (D) and, if desired, further the inorganic filler (E),but the mixing order thereof is not particularly limited. For example,all components may be en bloc mixed at the same time, or after any twocomponents are preliminarily mixed, remaining components may be addedthereto and mixed. At the time of melt-mixing the mixture of respectivecomponents, an extrude, a Banbury mixer, a roll mill or the like may beused.

Also, if desired, other thermoplastic resins such as α-olefin orα-olefin copolymer (e.g., polyethylene, polypropylene), styrene-basedresin (e.g., polystyrene, high-impact styrene), polycarbonate,polybutylene terephthalate, polyethylene terephthalate, polymethylmethacrylate, polyphenylene ether, polyphenylene sulfide, polysulfone,polyethersulfone, polyimide, polyetherimide and polyether ether ketonemay be added to the above-described components. Furthermore, variousadditives such as an antioxidant, an ultraviolet absorbent, a lightstabilizer, an antistatic agent, a lubricant, a dye, a pigment, aplasticizer, a flame retardant and a release agent may be added.

According to the present invention, a shaped article is obtained byshaping the thermoplastic resin composition described above. As for theshaping method, a commonly employed shaping method such as injectionmolding, extrusion molding, blow molding, vacuum molding and pressmolding can be used. In particular, injection molding and extrusionmolding are preferred. The thus-obtained shaped article may be subjectedto a secondary processing such as coating, vapor deposition andadhesion.

The shaped article of the present invention is excellent in the impactstrength, heat resistance, chemical resistance and paintability and canbe used for electric-electronic parts, machine parts and automobileparts such as automobile functional parts, automobile interior parts andautomobile exterior parts. In particular, the shaped article of thepresent invention is suitably used for automobile parts.

Examples of the automobile interior parts include register blade, washerlever, window regulator handle, knob of window regulator handle, passinglight lever, sun visor bracket, shift knob, door trim, armrest,instrument panel, console box, steering wheel, rearview mirror housing,door inner panel, air duct panel, window molding fastener, speed cableliner, belt lock striker and headrest rod holder.

Examples of the automobile exterior parts include two-wheeled automobileparts such as front cowl, rear cowl and side cover, and four-wheeledautomobile parts such as bumper, bumper corner, bumper skirt radiatorgrille, fog lamp reflector, hood, fender, door panel, side-view mirrorhousing, center pillar, air outlet louver, wheel, wheel cap, emblem,exterior trim and molding, sliding roof and tail lamp rim.

EXAMPLES

The present invention is described below by referring to Examples, butthe present invention is not limited thereto. In Examples, the “parts”and “%” are on a weight basis.

[Thermoplastic Resin Composition (1)]

Reference Example 1

(Production of Rubber-Like Polymer)

100 Parts of 1,3-butadiene, 0.3 parts of tert-dodecylmercaptane, 0.25parts of potassium persulfate, 2.5 parts of potassium oleate, 0.1 partof potassium hydroxide and 170 parts of pure water were charged into apressure vessel and after elevating the temperature to 65° C., thepolymerization was initiated. The diene-based rubber latex (b-(1))obtained after the completion of polymerization for 20 hours had a solidcontent of 37%, a weight average particle diameter of 65 nm and a swellindex of 20. The diene-based rubber latex (b-(2)) obtained after thecompletion of polymerization for 12 hours had a solid content of 25%, aweight average particle diameter of 50 nm and a swell index of 40. Theswell index of the rubber-like polymer was determined as describedbefore.

(Enlargement by Aggregation of Lubber-Like Polymer)

The diene-based rubber latex (b-(1)) prepared above was mechanicallyaggregated to obtain an enlarged diene-based rubber latex (b-1)containing a rubber-like polymer having a swell index of 36 and a weightaverage molecular weight of 300 nm. Separately, 0.1 part of acetic acidwas added to 100 parts by weight of the diene-based rubber latex (b-(2))prepared above and after mixing with stirring for 10 minutes, 10 partsof an aqueous 10% potassium hydroxide solution was added to obtain anenlarged diene-based rubber latex (b-2) having a solid content of 34%, aswell index of 41 and a weight average particle diameter of 300 nm.

(Production of Graft Polymer B)

65 Parts (as solid content) of the enlarged diene-based rubber latex(b-1) prepared above, 1.5 parts of sodium dodecylbenzenesulfonate and0.3 parts of potassium persulfate were charged into a stainless steelvessel and after elevating the temperature to 65° C., a monomer mixturecomprising 24.5 parts of styrene and 10.5 parts of acrylonitrile wascontinuously added over 5 hours to obtain a graft polymer latex.Thereto, 1 part of a phenol-based antioxidant and 2 parts of aphosphite-based antioxidant were added per 100 parts by weight (as solidcontent) of the graft polymer latex, and the resulting mixture wascoagulated, by using magnesium sulfate, dehydrated and dried to obtainGraft Polymer B-1. In this Graft Polymer B-1, the swell index of therubber-like polymer was 36, the weight average particle diameter thereofwas 320 nm, the rubber-like polymer content was 65%, and the numberaverage molecular weight of the acetone-soluble moiety was 22,000.

Also, Graft Polymer B-2 was obtained in the same manner as Graft PolymerB-1 except that 50 parts (as solid content) of the enlarged diene-basedrubber latex (b-2) was added with ferrous sulfate as the reducing agentin a redox catalyst system using cumene hydroperoxide as the initiator,the polymerization temperature was set to 50° C., and the entire amountof the monomer mixture comprising 38.5 parts of styrene and 11.5 partsof acrylonitrile was added at the initial stage. In this Graft PolymerB-2, the swell index of the rubber-like polymer was 41, the weightaverage particle diameter thereof was 290 nm, the rubber-like polymercontent was 50%, and the number average molecular weight of theacetone-soluble moiety was 49,000.

Production of Graft Polymer B-3

Graft Polymer B-3 was obtained in the same manner as Graft Polymer B-1except for reacting 40 parts of styrene and 15 parts of acrylonitrile inthe presence of 45 parts (as a solid content) of polybutyl acrylate. Inthis Graft Polymer B-3, the swell index of the rubber-like polymer was43, the weight average particle diameter thereof was 170 nm, therubber-like polymer content was 45%, and the number average molecularweight of the acetone-soluble moiety was 50,000.

Production of Graft Polymer B-4

Graft Copolymer B-4 was obtained in the same manner as Graft Polymer B-1except for reacting 21 parts of styrene and 9 parts of acrylonitrile inthe presence of 70 parts (as a solid content) ofethylene-propylene-non-conjugated diene copolymer rubber latex (ethylenepropylene: non-conjugated diene (5-ethylene-2-norbornene)). In thisGraft Polymer B-4, the swell index of the rubber-like polymer was 24,the weight average particle diameter thereof was 470 nm, the rubber-likepolymer content was 70%, and the number average molecular weight of theacetone-soluble moiety was 24,000.

(Production of Unsaturated Carboxylic Acid-Modified Copolymer C)

200 Parts of pure water, 0.3 parts of potassium persulfate and 2 partsof sodium dodecylbenzenesulfonate were charged into a stainless steelvessel and after elevating the temperature to 65° C. with stirring, amonomer mixture comprising 74 parts of styrene, 25 parts ofacrylonitrile, 1 part of methacrylic acid and 0.5 parts oftert-dodecylmercaptane was continuously added over 5 hours.Subsequently, the temperature of the reaction system was elevated to 70°C. and at this temperature, the reaction product was ripened for 1 hour,thereby completing the polymerization. Thereafter, the resulting polymerwas salted out by using calcium chloride, dehydrated and dried to obtainUnsaturated Carboxylic Acid-Modified Copolymer C-1. The number averagemolecular weight of the obtained Unsaturated Carboxylic Acid-Modified,that is, Methacrylic Acid-Modified Copolymer C-1 was 50,000.

Methacrylic Acid-Modified Copolymer C-2 was obtained in the same manneras in the production of Methacrylic Acid-Modified Copolymer C-1 exceptfor using a monomer mixture comprising 73 parts of styrene, 24 parts ofacrylonitrile, 3 parts of methacrylic acid and 0.5 parts oftert-dodecylmercaptane as the monomer mixture. The number averagemolecular weight of Methacrylic Acid-Modified Copolymer C-2 obtained was44,000.

Methacrylic Acid-Modified Copolymer C-3 was obtained in the same manneras in the production of Methacrylic Acid-Modified Copolymer C-2 exceptfor using a monomer mixture comprising 73 parts of styrene, 24 parts ofacrylonitrile, 3 parts of methacrylic acid and 1 part oftert-dodecylmercaptane as the monomer mixture. The number averagemolecular weight of Methacrylic Acid-Modified Copolymer C-3 obtained was26,000.

Methacrylic Acid-Modified Copolymer C-4 was obtained in the same manneras in the production of Methacrylic Acid-Modified Copolymer C-1 exceptfor using a monomer mixture comprising 72 parts of styrene, 23 parts ofacrylonitrile, 5 parts of methacrylic acid and 0.5 parts oftert-dodecylmercaptane as the monomer mixture. The number averagemolecular weight of Methacrylic Acid-Modified Copolymer C-4 obtained was46,000.

Furthermore, Methacrylic Acid-Modified Copolymer C-5 was obtained in thesame manner as in the production of Methacrylic Acid-Modified CopolymerC-2 except for using a monomer mixture comprising 73 parts of styrene,24 parts of acrylonitrile, 3 parts of methacrylic acid and 1.6 parts oftert-dodecylmercaptane as the monomer mixture. The number averagemolecular weight of Methacrylic Acid-Modified Copolymer C-5 obtained was20,000.

(Production of Copolymer D)

200 Parts of pure water and 0.3 parts of potassium persulfate werecharged into a pressure vessel and, after elevating the temperature to65° C. with stirring, a monomer mixture comprising 70 parts of styrene,30 parts of acrylonitrile and 0.3 parts of tert-dodecylmercaptane, and30 parts of an aqueous emulsifier solution containing 2 parts of sodiumdodecylbenzenesulfonate were each continuously added over 5 hours.Subsequently, the temperature of the reaction system was elevated to 70°C. and at this temperature, the reaction product was ripened for 3hours, thereby completing the polymerization. Thereafter, the resultingpolymer was salted out by using calcium chloride, dehydrated and driedto obtain Copolymer 0-1. The number average molecular weight of theobtained Copolymer D-1 was 89,000.

Also, Copolymer D-2 was obtained in the same manner as in the productionof Copolymer D-1 except for using 1.2 parts of tert-dodecylmercaptane.The number average molecular weight of the obtained Copolymer D-2 was60,000.

Examples 1 to 15 and Comparative Examples 1 and 2

Polyamide Resin A-2 (nylon 6 (1013B, number average molecular weight:13,000), produced by Ube Industries, Ltd.), Polyamide Resin A-4 (nylon 6(1022B, number average molecular weight: 22,000), produced by UbeIndustries, Ltd.), graft copolymer B, unsaturated carboxylicacid-modified copolymer C and copolymer D were mixed at a ratio shown inTable 1, melt-mixed at 250° C. by using a 30-mm twin-screw extruder,pelletized and then shaped by injection molding to prepare thermoplasticresin compositions as specimens, and their physical properties wereevaluated. The results are shown in Table 1. In the Table, the numericalvalue in the parenthesis of each component of the resin composition isthe number of parts by weight of each component, with the proviso thatthe polyamide resin is 100 parts by weight.

(Impact strength)

The impact strength was evaluated according to ASTM D-256 under theconditions of ⅛ inch and 23° C.

(Fluidity)

The melt viscosity (Pa·s) as an index for fluidity was measured at atemperature of 260° C. and a shear rate of 1,000 sec⁻¹ by using acapillograph (Capillograph 1C, manufactured by Toyo Seiki Seisaku-Sho,Ltd.).

(Heat Resistance)

The heat resistance was evaluated according to ASTM 0-648 under theconditions of ¼ inch and a load of 1.82 MPa.

(Flexural Modulus)

The flexural modulus was evaluated according to ASTM D-790.

(Chemical Resistance)

A strip-like specimen (150×10×2 mm) produced by injection molding wasfixed along a testing jig for the Bending Form Method, and a liquidchemical (2-ethylhexyl phthalate) was coated on the specimen. Afterallowing the specimen to stand for 48 hours in an environment at 23° C.,the change in the outer appearance was observed with an eye. Thechemical resistance was rated AA (good) when the outer appearance wasnot changed, and rated BB (moderate) when slightly changed.

(Paintability)

The paintability was evaluated according to JISK-5400. That is, atwo-liquid type urethane-based paint (Urethane PG60, produced by KansaiPaint Co., Ltd.) was spray-coated on the surface of a plate-likespecimen (160 mm×60 mm, thickness: 2.5 mm) in an environment at roomtemperature and relative humidity of 80% and after the passing of 120hours, the coating film was subjected to an adhesion test. Thepaintability was rated AA (good) when 1-mm squares (100 squares, n=2)were not separated, and rated CC (not good) when they separated.

(Particle Diameter of Rubber-Like Polymer)

The weight average particle diameter was measured by a Spectronic 21D(manufactured by Milton Roy) at a wavelength of 546 nm.

In Table 1, A-2 is a polyamide resin (nylon 6 (1013B), produced by UbeIndustries, Ltd.); A-4 is a polyamide resin (nylon 6 (1022B), producedby Ube Industries, Ltd.); B-1 is a graft polymer containing 65% of arubber-like polymer having a swell index of 36 and a weight averageparticle diameter of 320 nm, in which the styrene/acrylonitrile ratiowas 70/30 by weight and the number average molecular weight of theacetone-soluble moiety was 22,000; B-2 is a graft polymer containing 50%of a rubber-like polymer having a swell index of 41 and a weight averageparticle diameter of 290 nm, in which the styrene/acrylonitrile ratiowas 77/23 by weight and the number average molecular weight of theacetone-soluble moiety was 49,000; B-3 is a graft polymer containing 45%of a rubber-like polymer having a swell index of 43 and a weight averageparticle diameter of 170 nm, in which the styrene/acrylonitrile ratiowas 73/27 by weight and the number average molecular weight of theacetone-soluble moiety was 50,000; B-4 is a graft polymer containing 70%of a rubber-like polymer having a swell index of 24 and a weight averageparticle diameter of 470 nm, in which the styrene/acrylonitrile ratiowas 70/30 by weight and the number average molecular weight of theacetone-soluble moiety was 24,000; C-1 is a methacrylic acid-modifiedcopolymer having a methacrylic acid content of 1.0% and a number averagemolecular weight of 50,000; C-2 is a methacrylic acid-modified copolymerhaving a methacrylic acid content of 3.0% and a number average molecularweight of 44,000; C-3 is a methacrylic acid-modified copolymer having amethacrylic acid content of 3.0% and a number average molecular weightof 26,000; C-4 is a methacrylic acid-modified copolymer having amethacrylic acid content of 5.0% and a number average molecular weightof 46,000; C-5 is a methacrylic acid-modified copolymer having amethacrylic acid content of 3.0% and a number average molecular weightof 20,000; D-1 is a copolymer having an acrylonitrile/styrene ratio of32/68 by weight and a weight average molecular weight of 89,000; and D-2is a copolymer having an acrylonitrile/styrene ratio of 24/76 by weightand a weight average molecular weight of 60,000.

The thermoplastic resin composition of Comparative Example 1 which didnot contain an unsaturated carboxylic acid-modified copolymer wasinferior in the impact strength, fluidity, paintability and the like. Onthe other hand, the thermoplastic resin compositions of Examples 1 to 15all were excellent not only in the impact strength but also in thebalance between impact strength and fluidity. Also, as is apparent fromcomparison with the thermoplastic resin compositions of Examples 1 and2, the thermoplastic resin composition of Comparative Example 2 wherethe unsaturated carboxylic acid-modified copolymer used had a numberaverage molecular weight of 20,000 was inferior in the chemicalresistance and paintability. TABLE 1 Example Example Example ExampleExample Example Example Example Example 1 2 3 4 5 6 7 8 9 A-2 A-430(100) 30(100) 30(100) 30(100) 30(100) 60(100) 60(100) 60(100) 60(100)B-1 29(97)  B-2 38(127) 38(127) 38(127) 38(127) 25(42)  25(42)  25(42) 25(42)  B-3 B-4 C-1 32(107) 10(17)  C-2 12(40)  12(40)  24(80)  C-3 C-412(40)   2(3)   5(8)  10(17)  C-5 D-1 20(67)  29(97)  20(67)   8(27) D-2  5(8)  13(22)  10(17)   5(8)  R.C.[%] 19.0 19.0 19.0 19.0 19.0 12.512.5 12.5 12.5 Izod impact 1/8″ RT [J/m] 876 824 820 780 850 100 1531084 1137 strength 1/8″ −30° C. [J/m] 341 485 97 250 300 46 45 54 118Fluidity 1000 sec⁻¹ 354 289 323 388 398 194 187 218 272 Flexural modulus[MPa] 1,750 1,850 1,600 1,800 2,000 1,700 1,750 1,800 1,800 Heatresistance [° C.] 88 90 88 86 87 78 72 74 77 Chemical resistance AA AAAA AA AA AA AA AA AA Paintability AA AA AA AA AA AA AA AA AA ExampleExample Example Example Example Example Comparative Comparative 10 11 1213 14 15 Example 1 Example 2 A-2 30(100) 60(100) 30(100) 60(100) A-460(100) 30(100) 40(100) 30(100) B-1 B-2 25(42)  38(127) 35(88)  38(127)B-3 42(140) 33(55)  B-4 27(90)  21(35)  C-1 C-2 15(25)  C-3 12(40)  C-4 5(17)   5(8)   5(17)   5(8)  C-5 12(40)  D-1 20(67)  23(77)   2(3) 38(127) 14(23)  25(63)  20(67)  D-2 R.C.[%] 12.5 19.0 19.0 15.0 19.015.0 17.5 19.0 Izod impact 1/8″ RT [J/m] 850 660 152 149 140 135 90 459strength 1/8″ −30° C. [J/m] 93 97 65 40 61 37 35 67 Fluidity 1000 sec⁻¹398 303 238 232 255 229 100 285 Flexural modulus [MPa] 2,200 1,700 2,2152,068 2,219 2,090 2,000 1,700 Heat resistance [° C.] 68 90 90 76 93 7979 91 Chemical resistance AA AA AA AA AA AA BB BB Paintability AA AA AAAA AA AA CC CC[Thermoplastic Resin Composition (2)]

The physical properties of the shaped articles in Examples 16 to 28below were measured as follows.

(Fluidity)

The melt flow rate (MFR) was measured according to ASTM D-1238 under theconditions of 250° C. and a load of 5 kgf. The unit is g/10 min.

(Flexural Modulus)

The flexural modulus was measured according to ASTM D-790. Shape:thickness=⅛ inch.

(Impact strength)

The Izod impact strength was measured according to ASTM D-256.Thickness=¼ inch, temperature=23° C.

(Heat Resistance)

The thermal deformation temperature was measured according to ASTM D-648under the conditions of a thickness of ¼ inch and a load of 4.6 MPa or18.2 MPa.

[Resins and the Like Used]

(A) Polyamide Resin

-   A-1: Polyamide 6 (1011FB, produced by Ube Industries, Ltd., number    average molecular weight: 11,000)-   A-2: Polyamide 6 (1013B, produced by Ube Industries, Ltd., number    average molecular weight: 13,000)-   A-3: Polyamide 6 (1015SB, produced by Ube Industries, Ltd., number    average molecular weight: 15,000)-   A-5: Polyamide 6 (1015C2, produced by Ube Industries, Ltd., number    average molecular weight: 15,000, containing 2.0 parts by weight of    montmorillonite per 100 parts by weight of the polyamide resin)    Polyamide Resin A-5 was produced as follows. The spaces between    layers of montmorillonite as a layered silicate with one unit having    a thickness of 9.5 Å on average and an average one-side length of    about 0.1 μm were previously expanded by using 12-aminododecanoic    acid as the swelling agent to facilitate the intercalation of    monomers between layers, and then α-caprolactam was polymerized,    whereby the montmorillonite was uniformly dispersed in the    polyamide. Incidentally, when this material was measured by X-ray    diffraction, the interlayer distance was 100 Å or more.    (B) Graft Polymer-   B-1; a graft polymer containing 65% of a rubber-like polymer having    a swell index of 36 and a weight average particle diameter of 320    nm, in which the styrene/acrylonitrile ratio was 70/30 by weight and    the number average molecular weight of the acetone-soluble portion    was 22,000    (C) Methacrylic Acid-Modified Copolymer-   C-4: a methacrylic acid-modified copolymer having a methacrylic acid    content of 5.0% and a number average molecular weight of 46,000    (D) Copolymer-   D-2: a copolymer having an acrylonitrile/styrene ratio of 24/76 by    weight and a weight average molecular weight of 60,000    (E) Inorganic Filler-   E-1: Carbon fiber (fiber length: 6 mm, fiber diameter: 7 μm)-   E-2: Glass fiber (fiber length: 3 mm, fiber diameter: 10 μm)-   E-3: Montmorillonite (thickness: 9.5 Å, one-side length: 0.1 μM)

The graft polymer (B-1), methacrylic acid-modified copolymer (C-4) andcopolymer (D-1) were produced in the same manner as in Reference Example1.

Examples 16 to 28

The polyamide resin A, graft copolymer B, unsaturated carboxylicacid-modified copolymer C, copolymer D and inorganic filler E were mixedat ratios shown in Table 2, melt-mixed at 250° C. by using a 30-mmtwin-screw extruder, pelletized and then shaped by injection molding toprepare thermoplastic resin compositions as specimens, and theirphysical properties were evaluated. The results are shown in Table 2.TABLE 2 Example 16 17 18 19 20 21 22 23 24 25 26 27 28 Resin CompositionA-1 wt % 55 55 55 55 55 55 55 55 55 A-2 wt % 55 A-3 wt % 55 55 A-5* wt %(55) B-1 wt % 25 25 25 23 23 25 25 23 21 21 21 25 25 C-4 wt % 4 4 4 4 44 4 4 4 6 2 4 4 D-2 wt % 16 16 16 18 18 16 16 18 20 18 22 16 16 E-1 wt %5 5 5 5 5 5 5 E-2 wt % 10 20 20 E-3 wt % (1.1) Physical Properties ofMaterial MFR g/10 min 35 25 15 34 30 26 31 41 45 37 60 74 36 Flexuralmodulus GPa 4.3 4.3 4.3 3.5 5.0 5.2 2.7 4.3 4.5 4.5 4.6 2.2 2.3 Izodimpact strength J/m 84 82 80 78 108 113 62 67 61 68 55 112 106 Heatdistortion ° C. 207 140 temperature (4.6 MPa) Heat distortion ° C. 127124 125 123 171 164 93 127 143 136 150 83 81 temperature (18.2 MPa)*As for Polyamide A-5, the proportions of resin component andmontmorillonite (E-3) are separately shown.

INDUSTRIAL APPLICABILITY

As described in the foregoing pages, the thermoplastic resin compositionof the present invention comprises a polyamide resin, arubber-reinforced styrene-based resin, an unsaturated carboxylicacid-modified copolymer as a compatibilizing agent and, if desired, anaromatic vinyl-based monomer-vinyl cyanide-based monomer copolymer and,if desired, further comprises an inorganic filler, and by using,particularly, a polyamide resin having a number average molecular weightwithin the specified range, a rubber-reinforced styrene-based resin withthe acetone-soluble moiety having a number average molecular weightwithin the specified range, and an unsaturated carboxylic acid-modifiedcopolymer having a number average molecular weight within apredetermined range, the thermoplastic resin composition of the presentinvention can be excellent in the balance between impact strength andfluidity and also excellent in the heat resistance, chemical resistanceand paintability.

Accordingly, the shaped article comprising the thermoplastic resincomposition of the present invention can be used for electric andelectronic parts, machine parts, automobile parts such as automobilefunctional parts, automobile interior parts and automobile exteriorparts. In particular, the shaped article of the present invention can besuitably used for automobile parts.

1. A thermoplastic resin composition comprising the following components: (A) from 20 to 79.5 parts by weight of a polyamide resin; (B) from 20 to 79.5 parts by weight of a graft polymer, said graft polymer being obtained by, (a) in the presence of from 40 to 80 wt % of a rubber-like polymer having a swell index of 10 to 80 and a weight average particle diameter of 100 to 600 mm, (b) graft-polymerizing from 20 to 60 wt % of a monomer mixture comprising: (i) from 50 to 90 wt % of an aromatic vinyl-based monomer, (ii) from 10 to 50 wt % of a vinyl cyanide-based monomer, and (iii) from 0 to 30 wt % of another vinyl monomer copolymerizable with those monomers, in which the acetone-soluble moiety of the graft polymer has a number average molecular weight of 20,000 to 200,000; (C) from 0.5 to 60 parts by weight of an unsaturated carboxylic acid-modified polymer, said unsaturated carboxylic acid-modified polymer being obtained by copolymerizing from 0.05 to 20 wt % of an unsaturated carboxylic acid monomer, from 50 to 89.95 wt % of an aromatic vinyl-based monomer and from 10 to 49.95 wt % of a vinyl cyanide-based monomer, and having a number average molecular weight of 22,000 to 60,000; and (D) from 0 to 50 parts by weight of a copolymer, said copolymer being obtained by copolymerizing from 50 to 90 wt % of an aromatic vinyl monomer, from 10 to 50 wt % of a vinyl cyanide-based monomer and from 0 to 60 wt % of another vinyl-based monomer copolymerizable with those monomers; with the proviso that the total amount of the components (A) to (D) is 100 parts by weight.
 2. A thermoplastic resin composition comprising the following components: (A) from 20 to 79.5 parts by weight of a polyamide resin; (B) from 20 to 79.5 parts by weight of a graft polymer, said graft polymer being obtained by, (a) in the presence of from 40 to 80 wt % of a rubber-like polymer having a swell index of 10 to 80 and a weight average particle diameter of 100 to 600 nm, (b) graft-polymerizing from 20 to 60 wt % of a monomer mixture comprising: (i) from 50 to 90 wt % of an aromatic vinyl-based monomer, (ii) from 10 to 50 wt % of a vinyl cyanide-based monomer, and (iii) from 0 to 30 wt % of another vinyl monomer copolymerizable with those monomers, in which the acetone-soluble moiety of the graft polymer has a number average molecular weight of 20,000 to 200,000; (C) from 0.5 to 60 parts by weight of an unsaturated carboxylic acid-modified polymer, said unsaturated carboxylic acid-modified polymer being obtained by copolymerizing from 0.05 to 20 wt % of an unsaturated carboxylic acid monomer, from 50 to 89.95 wt % of an aromatic vinyl-based monomer and from 10 to 49.95 wt % of a vinyl cyanide-based monomer, and having a number average molecular weight of 22,000 to 60,000; (D) from 0 to 50 parts by weight of a copolymer, said copolymer being obtained by copolymerizing from 50 to 90 wt % of an aromatic vinyl monomer, from 10 to 50 wt % of a vinyl cyanide-based monomer and from 0 to 60 wt % of another vinyl-based monomer copolymerizable with those monomers; with the proviso that the total amount of the components (A) to (D) is 100 parts by weight; and (E) from 0.05 to 150 parts by weight of an inorganic filler.
 3. The thermoplastic resin composition as claimed in claim 2, wherein the number average molecular weight of the polyamide resin is from 10,000 to 20,000.
 4. The thermoplastic resin composition as claimed in claims 1, wherein the graft polymer is obtained by graft-polymerizing styrene and acrylonitrile in the presence of a rubber-like polymer.
 5. The thermoplastic resin composition as claimed in claims 1, wherein the amount of the unsaturated carboxylic acid monomer in the unsaturated carboxylic acid-modified copolymer is from 0.5 to 10 wt %.
 6. The thermoplastic resin composition as claimed in claims 1, wherein the amount of the unsaturated carboxylic acid monomer in the unsaturated carboxylic acid-modified copolymer is from 0.8 to 7 wt %.
 7. The thermoplastic resin composition as claimed in claims 1, wherein the unsaturated carboxylic acid in the unsaturated carboxylic acid-modified copolymer is methacrylic acid.
 8. The thermoplastic resin composition as claimed in claims 1, wherein the unsaturated carboxylic acid-modified copolymer is obtained by copolymerizing methacrylic acid, styrene and acrylonitrile.
 9. The thermoplastic resin composition as claimed in claims 1, which comprises a rubber-like polymer in the range from 8 to 40 wt %.
 10. The thermoplastic resin composition as claimed in claims 1, which comprises a rubber-like polymer in the range from 10 to 25 wt %.
 11. The thermoplastic resin composition as claimed in claims 2, wherein the inorganic filler is a layered silicate with one unit having a one-side length of 0.002 to 1 gm and a thickness of 6 to 20 Å.
 12. A shaped article comprising the thermoplastic resin composition claimed in claims
 1. 13. An automobile part obtained by shaping the thermoplastic resin composition claimed in claims
 1. 14. The thermoplastic resin composition as claimed in claim 2, wherein the graft polymer is obtained by graft-polymerizing styrene and acrylonitrile in the presence of a rubber-like polymer.
 15. The thermoplastic resin composition as claimed in claim 2, wherein the amount of the unsaturated carboxylic acid monomer in the unsaturated carboxylic acid-modified copolymer is from 0.5 to 10 wt %.
 16. The thermoplastic resin composition as claimed in claim 2, wherein the amount of the unsaturated carboxylic acid monomer in the unsaturated carboxylic acid-modified copolymer is from 0.8 to 7 wt %.
 17. The thermoplastic resin composition as claimed in claim 2, wherein the unsaturated carboxylic acid in the unsaturated carboxylic acid-modified copolymer is methacrylic acid.
 18. The thermoplastic resin composition as claimed in claim 2, wherein the unsaturated carboxylic acid-modified copolymer is obtained by copolymerizing methacrylic acid, styrene and acrylonitrile.
 19. The thermoplastic resin composition as claimed in claim 2, which comprises a rubber-like polymer in the range from 8 to 40 wt %.
 20. The thermoplastic resin composition as claimed in claim 2, which comprises a rubber-like polymer in the range from 10 to 25 wt %.
 21. A shaped article comprising the thermoplastic resin composition claimed in claim
 2. 22. An automobile part obtained by shaping the thermoplastic resin composition claimed in claim
 2. 